The planning of a surgery for implanting an intraocular lens includes a selection of a suitable intraocular lens from a large number of different types and models of intraocular lenses available on the market. The different models of intraocular lenses may differ with respect to, for example, the refractive index of the lens material, the curvatures of the lens surfaces, the axial distance of the lens surfaces from each other, the diameter of the lens, the type of the haptics, and other properties. There are also different types of intraocular lenses, such as intraocular lenses having aspheric lens surfaces or having lens surfaces having free form surfaces without rotational symmetry, intraocular lenses providing zones with different refractive powers, and intraocular lenses including diffractive optical elements.
The selection of the type and model of the intraocular lens to be implanted into a particular eye is commonly based on preoperative values determined from the eye, such as the visual defect, the curvature of the cornea, the distance between the corneal apex and the retina of the eye, i.e. the eye length, and the distance between the corneal apex of the eye and the crystalline lens, i.e. the anterior chamber length, and other suitable values. Heuristic formulas are typically used in order to determine properties of the intraocular lens based on one or more of the above preoperative values. Examples of such formulas include the Haigis formula, the Hoffer formula, the Holladay formula and the SRK/T formula.
The selection of the type and model of the intraocular lens to be implanted into a particular eye does not always provide the desired result since the desired postoperative faculty of sight of the eye is not achieved subsequent to the surgery and after healing of incisions introduced into the cornea of the eye during the surgery.